Waste Heat Recovery System and Method Thereof

ABSTRACT

A waste heat recovery system comprises a steam generator, a processor, a first heat exchanger, and a second heat exchanger. The steam generator generates an original steam using water. The first heat exchanger condensates the first steam and emit water and a second steam from the processor. The second heat exchanger condensates the second steam from the first heat exchanger. The second heat exchanger condensates the second steam from the first heat exchanger leaving water only. The water from the first heat exchanger and the second heat exchanger may be guided into the steam generator or into the first heat exchanger. The second heat exchanger comprises one or more pressure relief valve. The pressure relief valve operates when inner pressure of the second heat exchanger exceeds above a predetermined value.

BACKGROUND OF THE INVENTION

The present invention relates to a waste heat recovery system and method thereof. More particularly, this invention relates to a waste heat recovery system and method, which enables to minimize the amount of waste heat discarded from a thermal application.

In a thermal application such as a boiler, waste heat problem has been there all the time. Due to the first law of thermodynamics, it seems to be unavoidable that a part of heat input to a thermal application is output into outside of the thermal application. That is, since it is impossible to create a thermal application having 100% of efficiency, the residue heat, the heat input minus the word done by the thermal application, is always larger than zero.

The waste heat has been dumped out of the thermal application as a form of still hot water or steam.

Even though the train is not powered by a steam engine any more, a plurality of thermal applications are present in our technological society.

Accordingly, a need for a waste heat recovery system and method has been present for a long time considering the expansive usage thereof. This invention is directed to solve these problems and satisfy the long-felt need.

SUMMARY OF THE INVENTION

The present invention contrives to solve the disadvantages of the prior art.

An objective of the invention is to provide a waste heat recovery system and method thereof.

Another object of the invention is to provide a waste heat recovery system, in which a waste heat in water or steam can be captured back into the system.

Still another object of the invention is to provide a waste heat recovery system, which uses a plurality of heat exchangers or pumps.

A waste heat recovery system comprises a steam generator, a processor, a first heat exchanger, and a second heat exchanger.

The steam generator is configured for generating an original steam using water.

The processor is configured to use the original steam from the steam generator and emit water and a first steam

The first heat exchanger is configured to condensate the first steam and to emit water and a second steam from the processor.

The second heat exchanger is configured to condensate the second steam from the first heat exchanger.

The second heat exchanger may be configured to condensate the second steam from the first heat exchanger leaving water only.

The water from the first heat exchanger and the second heat exchanger may be guided into the steam generator.

The water from the first heat exchanger may be guided into the steam generator, and water from the second heat exchanger may be guided into the first heat exchanger.

The second heat exchanger may comprise one or more pressure relief valve.

The pressure relief valve may be configured to operate when inner pressure of the second heat exchanger exceeds above a predetermined value.

The waste heat recovery system may further comprise a first water pump disposed between the steam generator and the first heat exchanger, and the first water pump may be configured to pump water from the first heat exchanger into the steam generator.

The waste heat recovery system may further comprise a second water pump disposed between the first water pump and the first heat exchanger, and the second water pump may be configured to pump water from the first heat exchanger into the first water pump.

The second water pump may have a lower pumping capacity than the first water pump.

The first heat exchanger may be configured to work as a water tank, and the second heat exchanger may be configured to work as a water tank.

The waste heat recovery system may further comprise a check valve disposed between the first heat exchanger and the second heat exchanger, and the check valve may start operation when a pressure inside the first heat exchanger exceeds a predetermined value.

The waste heat recovery system may further comprise a plurality of pipes. The first pipe may be configured to deliver the original steam from the steam generator to the processor. The second pipe may be configured to deliver water and the first steam from the processor to the first heat exchanger. The third pipe may be configured to deliver water and the second steam from the first heat exchanger to the second heat exchanger. The fourth pipe may be configured to deliver water from the second heat exchanger to the first heat exchanger. The fifth pipe may be configured to deliver water from the first heat exchanger to the steam generator.

Another aspect of the invention provides a method for recovering waste heat in the waste heat recovery system.

The method comprises: generating the original steam at the steam generator; delivering the original steam to the processor, wherein the processor produces water and the first steam; passing water and the first steam through the first heat exchanger, wherein the first heat exchanger produces water and the second steam; passing water and the second steam through the second heat exchanger, wherein the second heat exchanger condensates the second steam; delivering condensate water from the second heat exchanger to the first heat exchanger; and delivering condensate water from the first heat exchanger to the steam generator.

The method may further comprise pumping water from the first heat exchanger to the steam generator using the first water pump disposed between the first heat exchanger and the steam generator.

The method may further comprise pumping water from the first heat exchanger to the first water pump using the second water pump.

Still another aspect of the invention provides a method for recovering waste heat in the waste heat recovery system, comprising: generating the original steam at the steam generator; delivering the original steam to the processor, wherein the processor produces water and the first steam; passing water and the first steam through the first heat exchanger, wherein the first heat exchanger produces water and the second steam; passing water and the second steam through the second heat exchanger, wherein the second heat exchanger condensates the second steam; delivering condensate water from the second heat exchanger to the steam generator; and delivering condensate water from the first heat exchanger to the steam generator.

The method may further comprise pumping water from the first heat exchanger to the steam generator using the first water pump disposed between the first heat exchanger and the steam generator.

The method may further comprise pumping water from the first heat exchanger to the first water pump using the second water pump.

Still another aspect of the invention provide a waste heat recovery system comprising: a steam generator configured for generating an original steam using water; a first processor configured to use the original steam from the steam generator and emit water and a first steam; a second processor configured to use the original steam from the steam generator and emit water and a second steam; and a heat exchanger configured to condensate the first steam and the second steam and emit water.

The advantages of the present invention are: (1) the waste heat recovery system captures steam from a heat exchanger and liquefies them to linger and recycle in the system; and (2) the waste heat recovery system facilitates the waste heat recovery using additional pumps.

Although the present invention is briefly summarized, the fuller understanding of the invention can be obtained by the following drawings, detailed description and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the present invention will become better understood with reference to the accompanying drawings, wherein:

FIG. 1 is a schematic block diagram of a waste heat recovery system according to an embodiment of the present invention;

FIG. 2 is a schematic block diagram of a waste heat recovery system according to another embodiment of the present invention;

FIG. 3 is a schematic block diagram of a waste heat recovery system according to still another embodiment of the present invention;

FIG. 4 is a flowchart illustrating a waste heat recovery method according to an embodiment of the present invention;

FIG. 5 is a flowchart illustrating a waste heat recovery method according to another embodiment of the present invention;

FIG. 6 is a flowchart illustrating a waste heat recovery method according to still another embodiment of the present invention;

FIG. 7 is a flowchart illustrating a waste heat recovery method according to still another embodiment of the present invention;

FIG. 8 is a schematic block diagram of a waste heat recovery system according to another embodiment of the present invention; and

FIG. 9 is a schematic block diagram of a waste heat recovery system according to still another embodiment of the present invention.

DETAILED DESCRIPTION EMBODIMENTS OF INVENTION

FIG. 1 is a schematic block diagram of a waste heat recovery system 10 according to an embodiment of the present invention. FIG. 2 is a schematic block diagram of a waste heat recovery system 10 according to another embodiment of the present invention. FIG. 3 is a schematic block diagram of a waste heat recovery system 10 according to still another embodiment of the present invention.

The waste heat recovery system 10 comprises a steam generator 20, a processor 30, a first heat exchanger 40, and a second heat exchanger 40.

The steam generator 20 is configured for generating an original steam using water.

The processor 30 is configured to use the original steam from the steam generator 20 and emit water and a first steam. The processor 30 may include a plurality kinds of thermal applications such as boiler systems and steam engines, which take in steam of high temperature and pressure to exert work to internal or external loads. The first steam usually has temperature and pressure lower than the original steam directly from the steam generator 20.

The first heat exchanger 40 is configured to condensate the first steam and to emit water and a second steam from the processor 30. The second steam usually has temperature and pressure lower than the first steam directly from the processor 30. Since the internal energy of the original steam or the first steam could not be controlled against the external load on the processor 30, the first heat exchanger 40 is unable to condensate all of the first steam.

The second heat exchanger 50 is configured to condensate the second steam from the first heat exchanger 40.

The second heat exchanger 50 may be configured to condensate the second steam from the first heat exchanger 40 leaving water only. The second heat exchanger 50 works to meet all the needs to condensate all the rest of the first steam, such that no steam may escape the system.

The water from the first heat exchanger 40 and the second heat exchanger 50 may be guided into the steam generator 20. In certain embodiments of the invention, the relative location of the first and second heat exchangers 40, 50 may be closer than the steam generator and one of the first and second heat exchangers 40, 50, in which case the connection between them may be simplified.

Alternatively, the water from the first heat exchanger 40 may be guided into the steam generator 20, and water from the second heat exchanger 50 may be guided into the first heat exchanger 40. Since condensate water is going to be reused in the steam generator 20, it can be guided directly from where it was condensed.

The second heat exchanger 50 may comprise one or more pressure relief valve 52 for relieving overly built pressure from the second heat exchanger 50. However, in a usual situation of normally operating system 20, the pressure relief valve 52 does not have to be operated.

Similarly the first heat exchanger 40 may comprise one or more pressure relief valve 42 for relieving overly built pressure from the first heat exchanger 40.

The pressure relief valve 42, 52 may be configured to operate when inner pressure of the first and second heat exchangers 40, 50 exceeds above predetermined values respectively.

The waste heat recovery system 10 may further comprise a first water pump 60 disposed between the steam generator 20 and the first heat exchanger 40, and the first water pump 60 may be configured to pump water from the first heat exchanger 40 into the steam generator 20.

The waste heat recovery system 10 may further comprise a second water pump 70 disposed between the first water pump 60 and the first heat exchanger 40, and the second water pump 70 may be configured to pump water from the first heat exchanger 40 into the first water pump 60.

The second water pump 70 may have a lower pumping capacity than the first water pump 60.

The first heat exchanger 40 may be configured to work as a water tank, and the second heat exchanger 50 may be configured to work as a water tank. Since the first heat exchanger 40 and the second heat exchanger 50 condense steam, they are configured to retain the condensate water to pump out to the steam generator 20.

The waste heat recovery system 10 may further comprise a check valve 80 disposed between the first heat exchanger 40 and the second heat exchanger 50, and the check valve 80 may start operation when a pressure inside the first heat exchanger 40 exceeds a predetermined value. The check valve 80 may close down passing of water or steam from the first heat exchanger 40 to the second heat exchanger 50 with the pressure under the predetermined value.

The waste heat recovery system 10 may further comprise a plurality of pipes as shown in FIG. 3. The first pipe 91 may be configured to deliver the original steam from the steam generator 20 to the processor 30. The second pipe 92 may be configured to deliver water and the first steam from the processor 30 to the first heat exchanger 40. The third pipe 93 may be configured to deliver water and the second steam from the first heat exchanger 40 to the second heat exchanger 50. The fourth pipe 94 may be configured to deliver water from the second heat exchanger 50 to the first heat exchanger 40. The fifth pipe 95 may be configured to deliver water from the first heat exchanger 40 to the steam generator 30.

Another aspect of the invention provides a method for recovering waste heat in the waste heat recovery system 10.

FIG. 4 is a flowchart illustrating a waste heat recovery method according to an embodiment of the present invention. FIG. 5 is a flowchart illustrating a waste heat recovery method according to another embodiment of the present invention.

The method comprises: generating the original steam at the steam generator 20 (S100); delivering the original steam to the processor 30, wherein the processor 30 produces water and the first steam (S200); passing water and the first steam through the first heat exchanger 40, wherein the first heat exchanger 40 produces water and the second steam (S300); passing water and the second steam through the second heat exchanger 50, wherein the second heat exchanger 50 condensates the second steam (S400); delivering condensate water from the second heat exchanger 50 to the first heat exchanger 40 (S500); and delivering condensate water from the first heat exchanger 40 to the steam generator 20 (S600).

The method may further comprise pumping water from the first heat exchanger 40 to the steam generator 20 using the first water pump 60 disposed between the first heat exchanger 40 and the steam generator 20 (S700) as shown in FIG. 5.

The method may further comprise pumping water from the first heat exchanger 40 to the first water pump 60 using the second water pump 70 (S800) as shown in FIG. 5.

Still another aspect of the invention provides a method for recovering waste heat in the waste heat recovery system 10.

FIG. 6 is a flowchart illustrating a waste heat recovery method according to still another embodiment the present invention. FIG. 7 is a flowchart illustrating a waste heat recovery method according to still another embodiment of the present invention.

The method comprises: generating the original steam at the steam generator 20 (S100); delivering the original steam to the processor 30, wherein the processor 30 produces water and the first steam (S200); passing water and the first steam through the first heat exchanger 40, wherein the first heat exchanger 40 produces water and the second steam (S300); passing water and the second steam through the second heat exchanger 50, wherein the second heat exchanger 50 condensates the second steam (S400); delivering condensate water from the second heat exchanger 50 to the steam generator 20 (S550); and delivering condensate water from the first heat exchanger 40 to the steam generator 20 (S600).

The method may further comprise pumping water from the first heat exchanger 40 to the steam generator 20 using the first water pump 60 disposed between the first heat exchanger 40 and the steam generator 20 (S700).

The method may further comprise pumping water from the first heat exchanger 40 to the first water pump 60 using the second water pump 70 (S800).

As shown in FIG. 8, still another aspect of the invention provide a waste heat recovery system 10′ comprising: a steam generator 20 configured for generating an original steam using water; a first processor 30 configured to use the original steam from the steam generator 20 and emit water and a first steam; a second processor 32 configured to use the original steam from the steam generator 20 and emit water and a second steam; and a heat exchanger 40 configured to condensate the first steam and the second steam and emit water. The heat exchanger 40 may accept cold water from outside and heat it up by heat-exchanging so as to send out hot water as illustrated.

The system 10′ may further comprise a makeup water tank 46, which accepts water and vapor from the processors 30, 32, condensate water falling from the heat exchanger 40, and receives cold water from outside. The water is sent from the makeup water tank 46 to the steam generator 20 through one or more check valves 97, 99 using a pump 44.

The waste heat recovery system 10′ may further comprise first and second water pumps 60, 62, first and second check valves 80, 82 as shown in FIG. 8.

In still another embodiment of the invention as shown in FIG. 9, the system 10′ may further comprise another pump 45. Furthermore, the system 10′ may further comprise other pumps (not shown) around the pump 45.

Each of the heat exchanger 40 and the steam generator 20 may further comprise a pressure relief valve 49, 29 as shown in FIGS. 8 and 9.

The system 10, 10′ may further have still another processors below the processor 32 as shown in FIGS. 8 and 9.

While the invention has been shown and described with reference to different embodiments thereof, it will be appreciated by those skilled in the art that variations in form, detail, compositions and operation may be made without departing from the spirit and scope of the invention as defined by the accompanying claims. 

1. A waste heat recovery system comprising: a steam generator configured for generating an original steam using water; a processor configured to use the original steam from the steam generator and emit water and a first steam; a first heat exchanger configured to condensate the first steam and emit water and a second steam from the processor; and a second heat exchanger configured to condensate the second steam from the first heat exchanger.
 2. The waste heat recovery system of claim 1, wherein the second heat exchanger is configured to condensate the second steam from the first heat exchanger leaving water only.
 3. The waste heat recovery system of claim 1, wherein water from the first heat exchanger and the second heat exchanger is guided into the steam generator.
 4. The waste heat recovery system of claim 1, wherein water from the first heat exchanger is guided into the steam generator, and wherein water from the second heat exchanger is guided into the first heat exchanger.
 5. The waste heat recovery system of claim 4, wherein the second heat exchanger comprises one or more pressure relief valve.
 6. The waste heat recovery system of claim 5, wherein the pressure relief valve is configured to operate when inner pressure of the second heat exchanger exceeds above a predetermined value.
 7. The waste heat recovery system of claim 1, further comprising a first water pump disposed between the steam generator and the first heat exchanger, wherein the first water pump is configured to pump water from the first heat exchanger into the steam generator.
 8. The waste heat recovery system of claim 7, further comprising a second water pump disposed between the first water pump and the first heat exchanger, wherein the second water pump is configured to pump water from the first heat exchanger into the first water pump.
 9. The waste heat recovery system of claim 8, wherein the second water pump has a lower pumping capacity than the first water pump.
 10. The waste heat recovery system of claim 1, wherein the first heat exchanger is configured to work as a water tank, and wherein the second heat exchanger is configured to work as a water tank.
 11. The waste heat recovery system of claim 1, further comprising a check valve disposed between the first heat exchanger and the second heat exchanger, wherein the check valve starts operation when a pressure inside the first heat exchanger exceeds a predetermined value.
 12. The waste heat recovery system of claim 1, further comprising: a first pipe configured to deliver the original steam from the steam generator to the processor; a second pipe configured to deliver water and the first steam from the processor to the first heat exchanger; a third pipe configured to deliver water and the second steam from the first heat exchanger to the second heat exchanger; a fourth pipe configured to deliver water from the second heat exchanger to the first heat exchanger; and a fifth pipe configured to deliver water from the first heat exchanger to the steam generator.
 13. A method for recovering waste heat in the waste heat recovery system of claim 1, the method comprising: generating the original steam at the steam generator; delivering the original steam to the processor, wherein the processor produces water and the first steam; passing water and the first steam through the first heat exchanger, wherein the first heat exchanger produces water and the second steam; passing water and the second steam through the second heat exchanger, wherein the second heat exchanger condensates the second steam; delivering condensate water from the second heat exchanger to the first heat exchanger; and delivering condensate water from the first heat exchanger to the steam generator.
 14. The method of claim 13, further comprising pumping water from the first heat exchanger to the steam generator using the first water pump disposed between the first heat exchanger and the steam generator.
 15. The method of claim 14, further comprising pumping water from the first heat exchanger to the first water pump using the second water pump.
 16. A method for recovering waste heat in the waste heat recovery system of claim 1, the method comprising: generating the original steam at the steam generator; delivering the original steam to the processor, wherein the processor produces water and the first steam; passing water and the first steam through the first heat exchanger, wherein the first heat exchanger produces water and the second steam; passing water and the second steam through the second heat exchanger, wherein the second heat exchanger condensates the second steam; delivering condensate water from the second heat exchanger to the steam generator; and delivering condensate water from the first heat exchanger to the steam generator.
 17. The method of claim 16, further comprising pumping water from the first heat exchanger to the steam generator using the first water pump disposed between the first heat exchanger and the steam generator.
 18. The method of claim 17, further comprising pumping water from the first heat exchanger to the first water pump using the second water pump.
 19. A waste heat recovery system comprising: a steam generator configured for generating an original steam using water; a first processor configured to use the original steam from the steam generator and emit water and a first steam; a second processor configured to use the original steam from the steam generator and emit water and a second steam; and a heat exchanger configured to condensate the first steam and the second steam and emit water. 